This proposal outlines approaches to assessment of bleomycin- and H2O2-mediated oxidative cell wall damage in Aspergillus fumigatus and Cryptococcus neoformans, both AIDS pathogens. The specific aims of this proposal are to identify cell wall targets of bleomycin in Saccharomyces cerevisiae. To this end, we will assay cell wall integrity and bleomycin susceptibility of bleomycin sensitive strains (blm mutants), cell wall mutants of known provenance and effect.